Push-button operated electric switch



, y 9- J. P. CORNISH 2,415,696

PUSH-BUTTON OPERATED ELECTRIC SWITCH Filed Oct. 24, 1946 2 SheetS-Shet 1 y 1949- I J. P. CORNISH 2,475,696

PUSH-BUTTON OPERATED ELECTRIC SWITCH Filed Oct. 24, 1946 2 Sheets-Sheet? 5 Q, a, 3 '8 a" a Q n) (n v m Q? g I V f//// 1: w

Q Q) I g D 3? I v Q v) m 53 O m m I v wftaam Patented July 12, 1949 PUSH-BUTTON OPEictATED ELECTRIC SWITiIH John Peter Cornish, Penarth, Wales, assignor to The Concordia Electric Safety Lamp Company Limited, Cardiff, Wales, a British company Application October 24, 1946, Serial No. 705,411 in Great Britain April 27, 1945 Section 1, Public Law 690, August 8, 1946 Patent expires April 2'7, 1965 Claims.

This invention relates to electric switches and t has among its objects to provide a switch that is proof against the passage of liquid or gas that may corrode the contacts, to provide a selfcontained switch that is applicable to articles such as electric handlamps, and to provide such a switch that is available for the control of more than one circuit.

According to the invention the switch comprises terminal contacts and a circuit-closing element sealed within a casing, and control means for the circuit closing element projecting outside the casing.

The circuit-closing element may conveniently take the form of a ball, drum, cylinder or plunger of conductive metal or it may comprise a body of non-conductive material, such as a plastic material, in or upon which conductive strips or surfaces are fitted or formed for engagement of the terminal contacts.

The invention further comprises the features of construction hereinafter described.

The invention is illustrated, by way of example, in the accompanying diagrammatic drawings.

Figure l is a longitudinal section of a construction of the switch.

Figure 2 is an end view of the switch represented in Figure 1 viewed from the operating end of the switch.

Figure 3 is an end View of the switch represented in Figure I viewed from the opposite end of the switch.

Figure 4 is a cross-section taken on the line 3-4 of Figure 1.

Figure 5 is a longitudinal section of a modified construction of the switch.

In carrying the invention into effect, by way of example, in the construction of a self-contained switch that is proof against the passage of liquid or gas and that is adaptable to a hand lamp, such as a miners electric lamp, as illustrated in Figures 1 to 4 of the accompanying drawings, the casing consists of a body I of ebonite or other insulating or non-conductive ma terial such as a plastic material, that comprises three parts of differing and graduated diameters axially disposed and is closed at the smaller end, :he first part, of largest diameter, having a bore ;hat is in two parts of differing diameters, the part 2 of the [bore of larger diameter being at ;he outer end of the casing and being formed with a screw thread 3 for the reception of a closng plate or ring 4 having a cooperating threaded )OZ'tlOIl. The second part 5 and the third part 6 of the of the smaller diameters, are bored each to an appropriate diameter as at "l and 8.

The second and third parts 5, ii of the casing serve to house the spring-pressed plunger 9 made of ebonite or other non-conductive material or of a plastic material, which is formed with a stem it of a diameter slidably to fit the bore 8 of the third part ii of the casing, of smallest di ameter, and with a head ii that is a clearance fit within the bore '1 of the second part 5 of the casing. The spring 52 is helical and is disposed between the head it and the shoulder I3 formed by the reduction of diameter at the junction of the bores "i, 8 of the second and third parts 5, 6 of the casing. The bore '1 of the second part 5 is continued for a short distance into the first part of the casing l and there are here disposed two terminal contacts it, 55 extending radially through the Wall of the said part and having pointed or spring ends protruding into the bore "1, or as may be required. Within the inner part it of the bore of the first part of the casing i there is disposed a ball H or silver, brass or other conductive metal that is a rolling fit in the bore. The head ll of the spring-pressed plunger 9 is shaped to avoid engagement with the terminal contacts i4, i5 and also to form an axial recess it of spherical curvature to serve as a seat for the ball ll. Thus, so long as the ball ii is not subjected to pressure to overcome the force exerted by the spring-pressed plunger 9, the latter will press the ball out of engagement with the terminal contacts it, it. It is the purpose of the operating element l to control this tendency at will.

At the shoulder formed by the changein diameter of the parts 2 and iii of the bore of the first part of the casing there is seated at transverse diaphragm 23 of rubber or a synthetic ma terial of the required elasticity eiiectively sealing the bore against the passage of liquid or gas and retained in position by a retaining ring 25. The ring it may be of ebonite or other nonconductive material or of plasticmaterial.

The operating element is is formed of eocnite or other non-conducting material or of material and comprises a cylindrical body 22 that is a sliding fit within the outer bore of the first part of the casing and is formed at the inner end with a cylindrical extension 23 of reduced eter to pass freely through the diaphragmqetain ing ring 2! and to bear upon the diaphragm ii by means of its end face 24 which is formed to a spherical curvature to correspond with that of the ball ll. At the outer end the element I9 151 formed with a cylindrical part or extension 25 of a diameter to fit slidably in the closing ring or plate 4 of .thecasingl and of atlengthtoflextend... outwardly toserve asa knob or handle by which the operating element [9 may be manipulated. 5 A sealing washer or packing rin 26 of a plastic: material or other material for the purpose is recessed into a peripheral channeliatataposit'ion:tor. bear upon the inner surface of the bore of their closing ring or plate 4. The operating elementrl9.19" is thus adapted to press the ballilliiiitocngageement with the terminal contacts....l.4l,l l5l'thnoughl the medium of the diaphragm 20. The positions of the operating element l9 maybe=determinedi: by the engagement of a spring ball cateh zl set t radially in the wall of the casing ltwithtanynones of a number of circular recesses 28 formedii'n-th'er bottom of a groove or channel 29 in the peripheral surface of the body 22 of the element and-set at" a small angle to a planettransverse to the axis. The. engagement "of: the ball catch 2 It in the:g;roolfie3 or channel 29':constrains the possible: movementof "the :elemientto a limited movement of rotation that risraccompanied by; a slightv axialmovement to movettheball I1 into, or-to permitit towmoveiout of, contact with the terminal contactsl'mand"; l5, the: recesses determining the required; positions,

The switch mayp-be mounted .upon;:;the-lamp;or: other articleto which itis-- applied :as' mayy'ben required :by, the construction ofthelamp sandwthae electrical connections may be made'totheetertminal contacts in any conventionalima-nner, such;. as ;by soldering bythe use of clamping screws' or. byother means;.

The switch hereinbefore; described may;- be: adapted to control two or more'circuits in aisim, ple manner asindicated, for examples-invbrokenc lines-in Figure 1,. by "the provision; ofal==stripgcon;- tactr30 extending longitudinally along theeboremm 16; of the" casing,- from: one. of .theterminahcon: tacts l'4,- l5and: disposedso-as alwaysaitorz betinzi contact with the ball ll throughout. its laxiala movement'and; an additionalterminal contact I 31.. WithgWhlCh' the;:bal1 Il may comeinto contacts" when retracted from. the two terminal contacts-c I4; I5,-;to. a determined extent. under: the :qforceu-ofl. thezspring-pressed plunger -9. The striphcontactr 30imay be a spring contact.

Itsisznot: essential that. the f body jof theicasingg shouldibe; formed in three.parts-ofldiffering di=- ameters: Theouter shape-of the casing ;I :may bee adapted tOJZthELaItiCIGiWith.Whlch ,theswitchdatev belusedzr In a construction of switch adapted for the controliof two circuits: alternatively, as illustrated .in Figure-.15 of "the accompanyingv drawings; the body: of the;.housing;or.xcasingisa:cylinder :3210f ebonite; or otherunnneconductingl material, suchra'sra-zplase tic material, thatisgmoulded go-rzotherw-ise formed; with aaclosedrend: 33 an'd a cylindricalwboren 4wthat 1 may have thei'inner closed"endg35scentrallh reecessed: at .36 toformv azseating: fortahelicarspring 3! to act upontth'e. plunger 38 andiincreasediin;

42, 43 and 44 and the ball 45 are advantageously of silver but may be of other conducting metal or alloy, The ball is a clearance fit.v inlthe bore 34 and while remaining alwaysin contact with the common terminal contact 42 is pressed always in the direction of the outer pin contact 43 by the plunger 38 under the action of the spring 31. Thezplunger 38 may be of a material such as that of-ft-he housing or casing. It has the outer part reduced in diameter to clear the inner pin contact 44": and. the outer end 46 advantageously of concave curvature to fit the ball.

The operating element is in two parts, the outer ofrlwhichis a cylindrical body 4! that protrudes axially-through a retainin ring 48 to a degree determined by a shoulder 49 formed by an increase in diameter of the body At, which shoulder is received in a corresponding annular recess at the inner side of the retaining ring 48. Th protruding part of the cylindrical body 49 serves by itsirotation' by hand to effect the operation offthe switch; For this purpose the inner end.face150 ofsth'e cylindrical body is inclined to the axis and:

is setyin. contact with a similar and complemene -tarygendface-5| formed on the second part of. theoperating element which is a cylinder 520i a.- length-ysufiicient to permitthe formation of'the inclined end face 5| and which has an: axial stema 53..loy which it may move the ball throughthe diaphragm 41. The second part 52 of-lthe-op eratiing element is constrained for movementonly in the; axialldirection'by the provision in the wall of the housing or casing of a uide pin Mthatz engageszin a longitudinal channel or groove 551m theeperiphery of'the cylinder 52. The retaining; ring 348 hasthe inner face recessed and internally screw -threaded at 56 to engage a screw-thread; formedlon the periphery of the'housing' or :casing; 321 at the outer end. The rin 48 is thus'effectivavto retain the parts of the operating element in,

th8":IB1atiV8'pOSitiOnS to permit them to function;

The diaphragm 4|, of rubber or a synthetic",

tivelythick annulus of an-inner diameter slight-- glyjgreater than that of the stem 53 of the second part 52 of the operating element and withnan;

axial-ipociiet likepart-51 of relatively thin walls intoiwhich-the said stem 53 extends and through which pressure is applied to the ball 45: .tdiaphragrn 4| is.-maintained in position on the shoulder: 43 of the bore 39 of the housing or casing 32 by a locking ring 58 fitting; the said bore:

In the operation of the switch the-rotation" iofttheaouter or first part 41 of theoperating element relatively to the; second part 52 :impels thelatter to move axially to press the. ball 45;

against the force "exerted by the spring-pressed.

plunger 38,into contact with the inner pin con-:-

itactJl' l andthusestablish a circuit through the: saidmcontact and the common terminal contact 42-. On...fur.ther. rotation of the first partiofzthel operating, element in the samedirection or. in the.

reverse direction, the plunger 38 is permitted'to diameter at 39, towards the: outer endiito;,fornrza 6511'0168113116 ball 45 out of contact with the inner shoulder All upon; which: may: be: seatedithea-flexible diaphragm-1.4L Atial:positionzlatixth'esinner? side of the shoulder. butznot':fanvremoyectrithes housing or casing is prepared: to: KBCGiVBLatT'OHEE side a common terminalkplug. "contact: 421and sirrz opposed positions but spaced: apart'thezcomplee mentary. pin contacts 433 44,-ithat protrudedntoi; the bore 34 of the-housing orcasing andrhavez their inner. end's bevell'edv or otherwise shapedn pin'conta'ct and thusbre'ak the. circuit. Furthenrotationpermits the ball to be forced by the plunger 3B"into'contact with theouter pin con tact= l3 for the closure of the second circuit.

The parts-of the operating-element and the retaininge ringmay be of'the materials hereinbe fore ementioned or-of other materials adapted for" The Preta-ining' ring 48 Y may be; pe:- riphera'lly screwethreadedzto serve also as meansathee-purpose;

effectively:toacontact':the:;bal1 4-52 Thescontactse fon mounting" the switch;

The:

By predetermining the distance between the contacts 43, 44 and the angle of the inclined end faces 50, 5| of the operating element the switch may be adapted as a micro-switch, the travel of the ball 45 being reduced as required for example to 20 thousandths of an inch.

The switch according to the invention may be used with advantage particularly for marine equipments and in all situations where the content of moisture in the air is high.

I claim:

1. An electric switch comprising an insulating casing having one end open and the other end closed by an integral wall, said casing further having at least three internal bores of different diameters, the smallest bore being at the closed end and the largest bore being at the open end with an intermediate bore therebetween, a shoulder formed on the intermediate bore by the largest bore, a flexible diaphragm held against said shoulder to provide a seal between said largest and intermediate bores, terminal contacts extending through the wall of the casing into the intermediate bore, a circuit-closing element movable lengthwise of the intermediate bore for engagement with said contacts, a plunger in slidable engagement with the wall of one of said bores, a spring holding said plunger in engagement with the circuit-closing element to urge the latter toward said diaphragm, and an operating element fitting within the largest bore and being rotatably adjustable therein for movements axially of the bore to press the diaphragm into engagement with the circuit-closing element for selectively maintaining the latter in circuit-opening or circuit-closing position.

2. An electric switch according to claim 1, in

which the possible movement of the operating element in the casing is determined by a guide channel or groove.

3. An electric switch according to claim 2, in which the operative and inoperative positions of the operating element are determined by spaced recesses and cooperating stop devices.

4. An electric switch according to claim 1, in

which the operating element is comprised of more than one part and the parts are relatively movable on the rotation of one part to effect an axial movement of a second part for the purpose of moving the circuit-closing element.

5. An electric switch according to claim {1, in which the relatively movable parts of the operating element are provided with co-operating cam surfaces.

JOHN PETER CORNISH.

REFERENCES CITED The following referenlces are of record in the file of this patent:

UNITED STATES PATENTS 

